Small camera modules often suffer from a phenomenon called lens shading. This is caused by properties of optics (lens) and micro lenses of an image sensor of the camera module. Severity of the problem is somewhat relational to how big the chief ray angle in micro lens aperture is, the chief ray angle being the angle of the incident rays passing through the center of the micro lens aperture. Different colours (green, blue, red) have different response in the micro lens and this can cause visible flaws in the resulting image. Lens shading is typically corrected for example by using calibrated 2D LUT (two dimensional look-up table) based lens shading correction.